Expansion of peripheral naturally occurring T regulatory cells by Fms-like tyrosine kinase 3 ligand treatment

Blood ◽  
2009 ◽  
Vol 113 (25) ◽  
pp. 6277-6287 ◽  
Author(s):  
Lee Kim Swee ◽  
Nabil Bosco ◽  
Bernard Malissen ◽  
Rhodri Ceredig ◽  
Antonius Rolink

Abstract Fms-like tyrosine kinase 3 ligand (FLT3L) plays a major role in dendritic cell (DC) biology. Deficiency of FLT3L causes a dramatic decrease in DC numbers, whereas increasing its availability (by repetitive injections for 7-10 days) leads to a 10-fold increase in DC numbers. In this study, we show that FLT3L treatment indirectly leads to an expansion of peripheral naturally occurring T regulatory cells (NTregs). The FLT3L-induced increase in NTregs was still observed in thymectomized mice, ruling out the role of the thymus in this mechanism. Instead, the increased number of NTregs was due to proliferation of preexisting NTregs, most likely due to favored interactions with increased number of DCs. In vitro, we show that DCs induce regulatory T-cell (Treg) proliferation by direct cell contact and in an interleukin-2–dependent, T-cell receptor–independent manner. FLT3L could prevent death induced by acute graft-versus-host disease (GVHD). This study demonstrates unique aspects in the regulation of Treg homeostasis by DCs, which were unappreciated until now. It also reinforces the relevance of FLT3L treatment in GVHD by its ability to increase both the number of tolerizing DCs and NTregs.

PLoS ONE ◽  
2014 ◽  
Vol 9 (11) ◽  
pp. e112242 ◽  
Author(s):  
Ghanashyam Sarikonda ◽  
Georgia Fousteri ◽  
Sowbarnika Sachithanantham ◽  
Jacqueline F. Miller ◽  
Amy Dave ◽  
...  

Blood ◽  
2009 ◽  
Vol 113 (4) ◽  
pp. 837-845 ◽  
Author(s):  
Guangming Gong ◽  
Lingyun Shao ◽  
Yunqi Wang ◽  
Crystal Y. Chen ◽  
Dan Huang ◽  
...  

Abstract Although Foxp3+ T regulatory cells (Tregs) are well documented for their ability to suppress various immune cells, T-cell subsets capable of counteracting Tregs have not been demonstrated. Here, we assessed phosphoantigen-activated Vγ2Vδ2 T cells for the ability to interplay with Tregs in the context of mycobacterial infection. A short-term IL-2 treatment regimen induced marked expansion of CD4+CD25+Foxp3+ T cells and subsequent suppression of mycobacterium-driven increases in numbers of Vγ2Vδ2 T cells. Surprisingly, activation of Vγ2Vδ2 T cells by adding phosphoantigen Picostim to the IL-2 treatment regimen down-regulated IL-2–induced expansion of CD4+CD25+Foxp3+ T cells. Consistently, in vitro activation of Vγ2Vδ2 T cells by phosphoantigen plus IL-2 down-regulated IL-2–induced expansion of CD4+CD25+Foxp3+ T cells. Interestingly, anti–IFN-γ–neutralizing antibody, not anti–TGF-β or anti–IL-4, reduced the ability of activated Vγ2Vδ2 T cells to down-regulate Tregs, suggesting that autocrine IFN-γ and its network contributed to Vγ2Vδ2 T cells' antagonizing effects. Furthermore, activation of Vγ2Vδ2 T cells by Picostim plus IL-2 treatment appeared to reverse Treg-driven suppression of immune responses of phosphoantigen-specific IFNγ+ or perforin+ Vγ2Vδ2 T cells and PPD-specific IFNγ+αβ T cells. Thus, phos-phoantigen activation of Vγ2Vδ2 T cells antagonizes IL-2–induced expansion of Tregs and subsequent suppression of Ag-specific antimicrobial T-cell responses in mycobacterial infection.


Blood ◽  
1984 ◽  
Vol 64 (1) ◽  
pp. 105-109
Author(s):  
MV Ragni ◽  
A Winkelstein ◽  
TL Evans ◽  
JH Lewis ◽  
FA Bontempo ◽  
...  

Unexplained lymphadenopathy, with or without accompanying symptoms, known as the “lymphadenopathy syndrome,” has been recognized in groups at risk for acquired immune deficiency syndrome (AIDS), namely, homosexuals and hemophiliacs. To date, however, no test has been defined that discriminates between asymptomatic individuals and those with adenopathy in these high-risk groups. The T colony assay, which measures T lymphocyte growth in soft agar and which allows selective T cell proliferation with minimal cell-cell contact, was evaluated in asymptomatic hemophiliacs. Significantly lower mean colony counts were found in eight hemophiliacs with adenopathy (HA), 763 +/- 348 (+/- SEM), than in 16 healthy hemophiliacs (HH) 3,044 +/- 661 (P less than .005), or than in 24 heterosexual control subjects, 3,964 +/- 395 (P less than .005). The in vitro addition of exogenous interleukin-2 (IL- 2) restored normal colony growth in the HA population. These results indicate that the T colony assay can detect abnormal cell-mediated immunity among hemophiliacs and specifically discriminates between asymptomatic hemophiliacs (HH) and those with adenopathy (HA). In addition, IL-2 may be of potential benefit in improving T cell defects in AIDS or the “lymphadenopathy syndrome”; however, this remains to be proven.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3883-3883
Author(s):  
Casper Paludan ◽  
Ryhor Harbacheuski ◽  
Rose Ann Murray ◽  
Megan Mendillo ◽  
Jorge Soler ◽  
...  

Abstract The placenta is a readily available and ethically non-controversial source of large amounts of therapeutic stem cells. Placenta Derived Adherent Cells (PDACs) are isolated from the placenta by one of several methods including physical disruption of tissue from several different anatomical sites within the placenta that include the amniotic membrane, chorion, placental cotyledons, or any combination thereof. Flow cytometry analysis showed that PDACs isolated from certain sites exhibit defined phenotypes, including for example CD200+ CD105+ CD73+ CD34− CD45− at percentages ≥70% and constitutively secrete IL-6, IL-8, and Monocyte Chemoattractant Protein-1 (MCP-1). PDACs demonstrate in vitro pluripotency in the adipogenic, osteogenic, and chondrogenic lineages. Furthermore, PDACs suppress T cell proliferation in certain Mixed Leukocyte Reaction (MLR) and the autologous EBV regression assays. Because secreted factors can powerfully modify immune responses and influence therapeutic use of cells, we report on the cytokine secretion in certain PDAC MLR and regression assays. Cytokines were measured on a Luminex system in supernatants from 6-day PDAC cultures, PDAC MLRs or PDAC regression assays. MLRs include PDACs, Dendritic Cells (DC)s, and T cells at DC/PDAC/T ratios 1/2/10. EBV regression assays included PDACs, EBV antigen-presenting cells (APC), and T cells at APC/PDAC/T ratios 1/2/10. Levels of IL-6 (11 ng/ml) and IL-8 (16 ng/ml) stayed constant in PDAC solo cultures, PDAC MLRs, and PDAC regression assays. MCP-1 concentration was 2 ng/ml in PDAC solo cultures, and non-suppressive control adherent cell MLRs and regression assays, but increased to 10 ng/ml in suppressed PDAC MLRs and PDAC regression assays. These values are consistent with reported MCP-1 serum levels. Interleukin-2 (IL-2) is both a T cell survival factor and an obligate factor for CD4+CD25+ T regulatory cells. T regulatory cells are not required for PDAC T cell suppression, but IL-2 levels consistently increase when MLR suppression by PDACs occurs. The CD4 MLR supernatants contained 65 pg/ml IL-2, and the CD8 MLR contained 35 pg/ml IL-2. In the 85% and 75% suppressed CD4 and CD8 PDAC MLRs, the IL-2 levels rose 5-fold to 331 pg/ml (CD4) and 2-fold to 67 pg/ml(CD8). These results indicate that IL-2 and MCP-1, traditionally known as stimulators of the immune response, may play a role in PDAC immune suppression. PDACs, which cause the secretion, may thus be useful therapeutic tools in the clinic.


2004 ◽  
Vol 72 (6) ◽  
pp. 3383-3390 ◽  
Author(s):  
Avi-Hai Hovav ◽  
Liuba Davidovitch ◽  
Gabriel Nussbaum ◽  
Jacob Mullerad ◽  
Yolanta Fishman ◽  
...  

ABSTRACT We reported previously that even though immunization with the recombinant mycobacterial 27-kDa lipoprotein (r27) induced a Th1-type response in mice, the vaccinated mice became more susceptible to challenge with Mycobacterium tuberculosis. In this study we show that r27 stimulates naive splenocytes to proliferate. Acylation of r27 was crucial for this effect, since a nonacylated mutant of r27, termed r27ΔSP, failed to stimulate splenocytes either in vitro or in vivo. Depletion experiments indicated that only B cells were proliferating in a T-cell-independent manner. We also found that r27 is recognized by TLR2, which is involved in mitogenic stimulation. Interestingly, r27 but not r27ΔSP induced high gamma interferon levels in splenocyte supernatants, whereas no significant interleukin-2 levels were detected. Since B-cell polyclonal activation might aggravate pathogen infection, we asked whether the antiprotective effect of the r27 lipoprotein is associated with its mitogenicity. We showed that, as in the case of r27, immunization of mice with the nonmitogenic r27ΔSP lipoprotein resulted in increased M. tuberculosis multiplication. We conclude that the antiprotective effect of the r27 lipoprotein must be linked to properties of the polypeptide portion of the lipoprotein rather than to its lipid moiety and its mitogenicity.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1345-1345
Author(s):  
Antonio Curti ◽  
Valentina Salvestrini ◽  
Michela Aluigi ◽  
Sara Trabanelli ◽  
Emanuela Ottaviani ◽  
...  

Abstract Indoleamine 2,3-dioxygenase (IDO) enzyme, which catalyzes the conversion of tryptophan into kynurenine, has been identified as a novel immunosuppressive agent by inhibiting T-cell proliferation and is involved in tolerance induction to tumors. We have recently shown that IDO protein is constitutively expressed in a significant subset of newly diagnosed acute myeloid leukemia (AML) patients, resulting in tryptophan catabolism along the kynurenine pathway and in the inhibition of allogeneic T-cell proliferation. Moreover, we demonstrated that IDO-expressing AML cells are capable to promote the differentiation of new CD4+CD25+Foxp3+ T regulatory cells (Treg cells). AML cells may be differentiated into leukemic dendritic cells (AML-DCs) which have increased immunogenicity and may be used as vaccine against leukemia. We in vitro generated DCs from 7 AML samples according to standard procedures and tested IDO expression and activity. At baseline, 5/7 AML samples expressed IDO, whereas 2/7 did not. After differentiation into DCs, IDO+ AML samples showed an up-regulation of IDO mRNA and protein, and IDO− AML cells turned positive. IDO-expressing AML-DCs were capable to catabolize tryptophan into kynurenine metabolite and, functionally, they inhibited allogeneic T-cell proliferation through an IDO-dependent mechanism. Similarly to undifferentiated IDO+ AML blasts, IDO-expressing AML-DCs induced a population of CD4+CD25+Foxp3+ Treg cells, which were capable to suppress in vitro allogeneic naïve T-cell proliferation. These data identify IDO-mediated catabolism as a general tolerogenic mechanism in AML cells, including AML-DCs and raise several concerns for the use of AML-DCs as cellular vaccine against leukemia.


Blood ◽  
1984 ◽  
Vol 64 (1) ◽  
pp. 105-109 ◽  
Author(s):  
MV Ragni ◽  
A Winkelstein ◽  
TL Evans ◽  
JH Lewis ◽  
FA Bontempo ◽  
...  

Abstract Unexplained lymphadenopathy, with or without accompanying symptoms, known as the “lymphadenopathy syndrome,” has been recognized in groups at risk for acquired immune deficiency syndrome (AIDS), namely, homosexuals and hemophiliacs. To date, however, no test has been defined that discriminates between asymptomatic individuals and those with adenopathy in these high-risk groups. The T colony assay, which measures T lymphocyte growth in soft agar and which allows selective T cell proliferation with minimal cell-cell contact, was evaluated in asymptomatic hemophiliacs. Significantly lower mean colony counts were found in eight hemophiliacs with adenopathy (HA), 763 +/- 348 (+/- SEM), than in 16 healthy hemophiliacs (HH) 3,044 +/- 661 (P less than .005), or than in 24 heterosexual control subjects, 3,964 +/- 395 (P less than .005). The in vitro addition of exogenous interleukin-2 (IL- 2) restored normal colony growth in the HA population. These results indicate that the T colony assay can detect abnormal cell-mediated immunity among hemophiliacs and specifically discriminates between asymptomatic hemophiliacs (HH) and those with adenopathy (HA). In addition, IL-2 may be of potential benefit in improving T cell defects in AIDS or the “lymphadenopathy syndrome”; however, this remains to be proven.


Blood ◽  
2006 ◽  
Vol 108 (8) ◽  
pp. 2655-2661 ◽  
Author(s):  
Devi K. Banerjee ◽  
Madhav V. Dhodapkar ◽  
Elyana Matayeva ◽  
Ralph M. Steinman ◽  
Kavita M. Dhodapkar

AbstractCD4+CD25+FOXP3+ regulatory T cells (Treg's) play an important role in the maintenance of immune tolerance. The mechanisms controlling the induction and maintenance of Treg's in humans need to be defined. We find that human myeloid dendritic cells (DCs) are superior to other antigen presenting cells for the maintenance of FOXP3+ Treg's in culture. Coculture of DCs with autologous T cells leads to an increase in both the number of Treg's, as well as the expression of FOXP3 protein per cell both in healthy donors and myeloma patients. DC-mediated expansion of FOXP3high Treg's is enhanced by endogenous but not exogenous interleukin-2 (IL-2), and DC-T-cell contact, including the CD80/CD86 membrane costimulatory molecules. DCs also stimulate the formation of Treg's from CD25- T cells. The efficacy of induction of Treg's by DCs depends on the nature of the DC maturation stimulus, with inflammatory cytokine-treated DCs (Cyt-DCs) being the most effective Treg inducers. DC-induced Treg's from both healthy donors and patients with myeloma are functional and effectively suppress T-cell responses. A single injection of cytokine-matured DCs led to rapid enhancement of FOXP3+ Treg's in vivo in 3 of 3 myeloma patients. These data reveal a role for DCs in increasing the number of functional FOXP3high Treg's in humans.


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